In Situ Switch Testing via Functional Reflectometry

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Solution Overview

Problem

Conventional methods for testing switches and other contacts in semiconductor interface hardware require time-intensive iterations or costly special circuitry, making them inefficient and costly for single-pass functional testing.

Innovation Solution

The implementation of an in situ functionality testing method using Functional Reflectometry Test (FRT) that allows for the testing of switches and other connect/disconnect points while they are connected to Automatic Test Equipment (ATE), utilizing existing ATE resources and software without additional hardware, and performing full functional testing in both open and closed states as single vector tests.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional testing methods (manual probing or loopback with feedback) are used to test switches, then testing can be performed, but test time becomes very long and hardware complexity increases

Engineering Contradiction:

Improveswitch functionality detectionVSAvoidtest time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical probing with automated electrical signal injection and reflection measurement. The test system automatically injects test signals through the switch and measures reflected signals to determine switch state, eliminating manual operations and reducing test time significantly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses feedback from reflected test signals to determine switch functionality. By measuring the reflected signal characteristics and comparing them against expected values, the system automatically detects whether the switch is functioning correctly without requiring manual intervention or complex iterative testing.

Inventive Principle:

Principle #23Feedback

2Extent of automation

If loopback method with feedback is used to test switches, then automated testing is achieved, but hardware complexity and additional circuitry are required

Engineering Contradiction:

Improveautomated switch testingVSAvoidtest circuitry complexity

Core Design Contradiction:

Extent of automationVSDevice complexity

Solution Approach 1:

The patent makes the existing ATE channel resources universal by enabling them to perform both device testing and switch testing functions. The same test channels used for semiconductor device testing can also test switches in situ, eliminating the need for dedicated switch test circuitry and reducing overall hardware complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The test system uses its own existing resources (ATE channels, signal generation and measurement capabilities) to test the switches without requiring external specialized equipment. The system serves itself by utilizing its built-in test resources to perform switch functionality testing, thereby avoiding additional hardware requirements.

Inventive Principle:

Principle #25Self-service

3Reliability

If iterative functional measurements are used to test switches, then comprehensive testing is achieved, but test time becomes prohibitive during production

Engineering Contradiction:

Improveswitch functional verificationVSAvoidproduction throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent performs preliminary characterization of the test system (measuring known reflection values for open and closed switch states) before actual switch testing. This preliminary action establishes reference data that enables rapid comparison during production testing, eliminating the need for time-consuming iterative measurements and significantly improving production throughput.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method significantly reduces test time overhead, enabling fast and efficient testing of switches and other electrical connect/disconnect points, with total test time less than 10 ms, and allows for concurrent execution on every test channel, minimizing hardware complexity and costs.

Implementation Method 1

The test signal is launched... A reflected signal is expected to return... looking for expected reflections of test signals

Methodology Applied

Scientific EffectSignal reflection: Reflection

Data Source

PatentUS11555856B2Method for in situ functionality testing of switches and contacts in semiconductor interface hardware

Publication Date: 2023.01.17 CELERINT LLC

AI summary

A method is provided for in situ functionality testing of electrical switches using a Functional Reflectometry Test (FRT) of switches on the signal path of electrical circuits in a semiconductor interface. The method includes initiating the functionality testing of the electrical switches in situ, wherein the functionality of the electrical switches is tested while the electrical switches are connected to the Automatic Test Equipment (ATE) and are in-use testing semiconductors. The method also includes conducting full Functional Reflectometry Testing of the electrical switches in situ in an open switch state and a closed switch state to determine whether each of the electrical switches is one of fully functional, stuck closed, and stuck open, wherein testing for each state is performed as a single vector functional test to minimize test time overhead.